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Why can't I work satellites?

Discussion in 'Satellite and Space Communications' started by KJ4PSU, Nov 18, 2009.

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  1. KJ4PSU

    KJ4PSU Ham Member QRZ Page

    I recently built a 4-element handheld yagi beam for 440. Its a really great design and has working really well. I get our 442.700 repeater really well and haven't had many chances to work it using simplex. Today, I had a south to north pass of the AO-51 satellite that went directly over my house. 90 degrees vertical over my house! I tuned the handheld to the receive frequency( I tried both frequencies and adjusted for dopplar as the bird made its pass) and I heard nothing the entire pass. Granted it was around 5:40 eastern time and maybe ppl were busy getting home from work, but I figured I would hear at least one person. I used the HRD satellite tracking program to adjust the elevation. Technically I did everything right, why didn't I hear anything? Any help will be greatly appreciated!
  2. K9STH

    K9STH Ham Member QRZ Page

    Can you hear your own signal? To really work the satellites reliably you have to run full duplex (being able to receive the satellite downlink at the same time you are transmitting).

    Glen, K9STH
    AMSAT 239/LM 463
  3. KF7AYS

    KF7AYS Ham Member QRZ Page

    Would a second radio count???
  4. KA0HCP

    KA0HCP XML Subscriber QRZ Page

    November 16 - November 19

    38k4 BBS, L/U
    Uplink: 1268.700 MHz 9k6 FM
    Downlink: 435.150 MHz 38k4 FM

    Here is the operating mode for todays four day window. Were you configured to copy this packet bulletin board mode?

    AO51 has been operating in various modes and frequencies most of this year. "Ya' can't tell the players without the program" as they say in baseball. The control team publishes a monthly sked. The best way to check is at the AMSAT board,

    Last edited: Nov 18, 2009
  5. K9STH

    K9STH Ham Member QRZ Page


    I always use a separate receiver when working the satellites. MUCH easier than trying to use a single unit even if the receiver works independently from the transmitter (cross band).

    Glen, K9STH
    AMSAT 239/LM 463
  6. WA4OTD

    WA4OTD Ham Member QRZ Page

    There is always traffic on every pass. If you don't hear it then something is wrong on your end.

    I found:
    my sense of direction is iffy to begin with. Scan wider than you think is necessary.
    The bird spins you you need to be able to rotate you antenna as you are scanning the sky.
    You have to have your squelch open.
    There are times the link is off.
  7. KJ4PSU

    KJ4PSU Ham Member QRZ Page

    I've only been a ham for about a month and a half now. I built this homebrew yagi to be able to work satellites and to do rdf. Like I said earlier, I'm able to pick up our 440 repeater here in town. These are the steps I took today:

    -Squelch all the way off
    -Followed the track of the bird with tracking software
    -I kept moving the antenna around to change polorazation
    -I used a compass to find start and finish locations, it was pretty easy since it was a South to North pass
    -I adjusted for dopplar
    -I checked AMSAT and all modes were operational

    I didnt intend to talk to the bird today, just be able to listen and see if I could pick up any QSO's. A little disappointed that I didn't hear anything. What do you suggest now?
    Last edited: Nov 18, 2009
  8. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    Try again, lots of times.

    I worked (and maybe Glen did, too -- I forget) the first pass of the first operational amateur satellite transponder, which was OSCAR-VI in 1972. I have the certificate for that, as everyone who worked the first pass did.

    That was 2m up/10m down.

    It was like inventing the wheel, and I'll never forget the feeling.:p

    Keep at it. Technology has greatly advanced since then.
  9. WA4OTD

    WA4OTD Ham Member QRZ Page

    Just guessing,
    1. The receive antenna does need to be pretty good. Even rubber ducks will pick up local repeaters. With 4 element you should hear repeaters you cannot hear on your HT antenna. If you can measure the gain of your antenna to know it is working right that is even better.
    2. I don't know your tracking software or how you aligned the azimuth and elevation degrees but they need to be pretty accurate.
    3. Suggestion to use headphone and mic is great. I can put my FT51R in DUP mode and transmit and receive at the same time.

    Can you take you homemade antenna and hold it and point? I just worry everything is right in the automated setup but that is neat!
    Check the gain vs HT antenna on the next town repeater. Or check signal strenght on beam vs HT antenna.
    Trees can cause a problem but probably not now!

    When I built my Cheap LEO antenna it sounded good at first but I could not hear the bird. I had left about 1/4 inch extra on all elements. I cut each element exact and big difference in receive and now hear easily.

    I have had times where there was nothing there and no announcement. Try several times. Try the other birds:
    AO-27: 145.850 mHz uplink (no PL tone) and 436.795 mHz downlink.
    AO-51: 145.920 mHz uplink (no PL tone) and 435.300 mHz donwlink.
    SO-50: 145.850 mHz uplink (WITH a 67.0 Hz PL tone) and 436.795 mHz downlink.
  10. WA4OTD

    WA4OTD Ham Member QRZ Page

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